The present application is generally related to machine current limiting for permanent magnet synchronous machines for electric power steering systems.
Permanent Magnet Synchronous Machines (PMSMs) are widely used in electric drive applications owing to their high power density, superior control performance and reliability. Typically, torque control of PMSMs is performed indirectly through feedback current control typically utilizing current and position measurements. Field Oriented Control (FOC) is the most commonly used technique for current control, in which all AC signals are transformed into DC signals via a reference frame transformation. The control system is then implemented in the synchronously rotating or d/q reference frame.